Improvement in rendering compasses insensible to local attraction



. ZSheets-Sheet GVISBORNF. & SIMPSON.

Compass.

No. 41.839. Patented March 8, 1864.

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' N. PETERS, Phumumngmphur, waehinghn. D. c,

Unirse @rares l Fatemi Ormes.

JNO. S. GISBORNE, OF BIRKENHEAD, AND WILLIAM SIMPSON, OF LIVER- POOL, ENGLAND.

IMPROVEMENT vIN RENDERING COll/IPASSES INSENSIBLE T0 LOCAL ATTRACTION.

Spccilication forming parut of Letters Patent No. ILSSB, dated March 8, 1864.

To all whom it may concern:

Be it known that we, JOHN SAGHEVERELL GISBORNE, of Birkenhead, in the county ot' Chester, telegraphic engineer, and WILLIAM SIMPSON, of Liverpoool, in the county of Lancaster, gentleman, both in that part of the United Kingdom of Great Britain and Ireland called England, have invented a new and useful Improvement in Means for Rendering Ships7 and other Compasses Insensible to Local Attraction and We do hereby declare that the following is a full and exact description of the construction and operation thereof', reference being had to the accompanying sheet of drawings, making a part ot' this specification, and to the letters of reference thereon-thatis to say Our invention consists of the use or employment of electricity to render insensible to local attraction or to overcome or counterchcck the local intluences which have so often and so seriously affected the magnetic needles ortheir equivalents in mariners7 compasses; and although our said invention is more particularly serviceable in compasses to be used on board ship, it is not exclusively so applicable, las it may advantageouslyform part of or be usedin connection with compasses to be elsewhere employed.

'Ihe best mode or arrangement with which we are acquainted for carrying our saidinvention of the use or employment of electricity for the purpose above named into effect consists in passing a current of electricity from au ordinary battery through a coil of insulated copper wire wound around a hollow conical or semi-spheroidal compass-box, or wound around a hollow conical or semi-spheroidal shaped dish encircling the compass-box. In either of these arrangements the magnetic or compass needle rests on a center point in' the usual way at a short distance below ahorif zontal line drawn acrossthe terminationof the said coil and below the mouth or termination of the conical or semi-spheroidal shaped box or dish, the leading features of construction of the compasses at present in use being retained.

hcreinbcfore mentioned, and in doing so reterence will bc made to the illustrative sheet ot' drawings herewith, in whichp Figure I is a perspective view, Fig. 2 a side elevation with part of the binnacle-frame removed, Fig. 3 a vertical section, and Fig.4a birds-eye view with the cover removed, all of a binnacle and compass for use at sea, and with a conical-shaped compass-box. Fig. 5 is a side elevation with part of the binnacleframe removed, Fig. 6 is a vertical section, and Fig. 7 is a birds-eye view with the cover removed,all of a binnacle and compass for use at sea, the ordinary compass-box being encircled by and attached to a semispheroidal shaped dish, which latter supports the pin on which the needle and card are balanced.

In Figs. It, 2, 3, and 4 the same letters of reference denote the `same parts. a, represents the binnacle; b,the compass-bow; c,the steclpin for carrying the needle d and card c;

j', the compass-box, made of sheet-copper or other vmaterial into the conical shape shown,

and supported on gimbals g, as in ordinary pass box or cone f. rIhe insulated wires are here shown to be two in number; but oneonly or any larger number may be employed. Atj they are connected, after sufficient slack has been left for free movement of the compass, to and communicate with the battery k, (shown as of the ordinary sulphate77 description,) although any other kind of battery or means of maintaining a continuous current of electricity would answer the same purpose 5 Z, the glass cover. m shows a protectiu g cover or hood, ot' gutta-percha or other material, preferably impervious to moisture.

In Figs. 5, 6, and 7 like letters of reference denote the same parts. a represents the bin nacle; b', thev compass-bow; c', the needlecarrier; d', the needle; e', the card; j", the compass-box, such as is at present in use, and to which is here shown attached the semi-spheroidal shaped dish or vessel g', that both of them may be carried on or by the gimbals t; t', the glass cover; j', the projecting pins; 7c', the insulated circuit wire orwires or communicator or communicators of the electricity generated in the battery l', and connected by the screws m; n', thel gutta-percha or other protecting-hood.

To arrange or set either of the apparatus above described for use, it is only necessary to connect the wires to the battery, when, if the insulation is good, a continuons cnrrentof electricity passes from one pole of the battery to the other through the coil, and in so doing the effect is to counteract practically all local attraction of the magnetic needle in ships and other compasscs.

Having now described the nature of our said invention and the best construction orarran gement of parts with which we are acquainted for carrying the same into eii'ect, We would have it understood that we do not confine ourselves to the use or employment of the apparatus herein described, nor tothe use or em gloyment of any particular-*kind of apparatus;

Before us- J oI-IN THOMSON KING, Patent Agent, 4. Clayton Square, Liverpool..

J oHN DAVrEs, Clark to the said John Thomson King. 

